Methods for preparing squalene

ABSTRACT

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T 1  (b) a denaturing distillation carried out at a temperature T 2 ; wherein steps (a) and (b) may be performed in either order; T 1  and T 2  are sufficient to cause squalene to boil; T 2 &gt;T 1 ; and T 2 &gt;200° C.

RELATED PATENT APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/696,591 filed on Feb. 21, 2013, now U.S. Pat. No. 9,199,897, which isa National Phase Application of PCT/IB2011/001397 filed May 12, 2011,which claims the benefit of U.S. provisional application 61/395,448filed May 12, 2010. The International Application was published as WO2011/141819 on Nov. 17, 2011.

This application is a divisional of U.S. application Ser. No. 13/696,591filed on Feb. 21, 2013, which is a National Phase Application ofPCT/IB2011/001397 filed May 12, 2011, which claims the benefit of U.S.provisional application 61/395,448 filed May 12, 2010. The InternationalApplication was published as WO 2011/141819 on Nov. 17, 2011.

The foregoing applications, and all documents cited therein or duringtheir prosecution (“appln cited documents”) and all documents cited orreferenced in the appln cited documents, and all documents cited orreferenced herein (“herein cited documents”), and all documents cited orreferenced in herein cited documents, together with any manufacturer'sinstructions, descriptions, product specifications, and product sheetsfor any products mentioned herein or in any document incorporated byreference herein, are hereby incorporated herein by reference, and maybe employed in the practice of the invention. More specifically, allreferenced documents are incorporated by reference to the same extent asif each individual document was specifically and individually indicatedto be incorporated by reference.

TECHNICAL FIELD

This invention is in the field of manufacturing squalene having a puritysuitable for pharmaceutical applications.

BACKGROUND ART

Shark liver oil contains a branched, unsaturated terpenoid calledsqualene, (C₃₀H₅₀; [(CH₃)₂C[═CHCH₂CH₂C(CH₃)]₂═CHCH₂—]₂;2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosa-hexaene; CAS RN7683-64-9). Squalene is known for use in oil-in-water emulsions in humanvaccines, for instance the MF59 emulsion that is used for adjuvantinginfluenza vaccines. Squalene is also used in other pharmaceuticalproducts (e.g. ointments, suppositories) and in cosmetics.

Current sources for squalene are primarily fish oils, and in particularshark liver oils. There can be problems associated with the use ofsqualene extracted from shark liver oil, particularly if rigorousmanufacturing standards (such as those used during the production ofMF59 by Novartis) are not upheld. For instance, sharks may be infectedby pathogens that are also infectious for humans or that producesubstances that are harmful to humans, and TSE or TSE-like shark agentsmay exist [e.g. references 1-3]. Furthermore, sharks can contain humantoxins, such as carchatoxin. In addition, sharks can contain proteins towhich humans can be allergic. A common fish protein to which humans areallergic is parvalbumin which is found in sharks. Thus cheap low-gradesources of squalene are not suitable for human pharmaceutical use. Therisk of harm to a human recipient may be heightened in situations wheresqualene is part of an immunological adjuvant because, by definition,the adjuvant may induce a strong unwanted immune response against theimpurity.

It would be useful to find further and improved processes for preparingsqualene that is suitable for pharmaceutical use, i.e. a product thatmeets regulatory standards and does not contain contaminants, pathogens,viruses, human toxins or proteins that could be harmful to humans. Theprocess of the present invention is particularly useful for thepurification of squalene derived from shark liver oil.

DISCLOSURE OF THE INVENTION

The present invention provides a method for preparing squalene from acomposition comprising squalene from an animal source, said methodcomprising steps of: (a) a purification distillation carried out at atemperature T₁; (b) a denaturing distillation carried out at atemperature T₂; wherein steps (a) and (b) may be performed in eitherorder; T₁ and T₂ are sufficient to cause squalene to boil; T₂>T₁; andT₂≧200° C. The animal source is typically a fish source, such as sharkliver oil (or an extract thereof) i.e. the invention provides a methodfor preparing squalene from shark liver oil or from a shark liver oilextract.

The present invention further provides a method for preparing squalenefrom a squalene-containing composition, comprising steps of (a) apurification distillation carried out at a temperature T₁; (b) adenaturing distillation carried out at a temperature T₂; wherein steps(a) and (b) may be performed in either order; T₁ and T₂ are sufficientto cause squalene to boil; T₁<140° C. and T₂≧200° C. Thesqualene-containing composition can usefully be shark liver oil or anextract thereof.

The present invention further provides a method for re-distillation of acomposition comprising at least 99% squalene, said re-distillation beinga denaturing distillation carried out at a temperature T₂, whereinT₂≧200° C. This re-distillation may reduce the moisture content of thecomposition e.g. to ≦0.01%.

The method of the present invention can be used to produce a productthat is suitable for pharmaceutical applications. In particular, themethod of the present invention can be used to produce purified squalenethat does not contain contaminants, pathogens, viruses, human toxins orproteins, in particular the protein parvalbumin, which could be harmfulto humans.

The present invention further provides a method for the manufacture ofan oil-in-water emulsion, comprising preparing an emulsion usingsqualene prepared according to the methods described above.

The present invention further provides a method for preparing a vaccinecomposition, comprising preparing an emulsion as described above andcombining the emulsion with an antigen.

The present invention further provides a method for preparing a vaccinekit comprising preparing an emulsion as described above and packagingthe emulsion into a kit as a kit component together with an antigencomponent.

The present invention further provides squalene prepared according tothe methods of the present invention.

The present invention further provides an oil-in-water emulsioncomprising squalene prepared according to the methods of the presentinvention.

The present invention further provides a vaccine comprising squaleneprepared according to the methods of the present invention.

The present invention further provides the use of squalene preparedaccording to the methods of the present invention in a vaccine.

Purification Distillation

The composition comprising squalene may be derived from any suitablesource, e.g. black liquor soap skimmings; tall oil soap; crude tall oil;tall oil pitch; sugarcane oil; residues from extraction, degumming, andrefining of oils and fats; distillation residues of fatty acids andesters; deodorization distillates of vegetable oils; olive oil; soybeanoil; rice bran oil; shark liver oil; beef tallow; coffee oil; fish oil;cod liver oil; wheat germ oil; corn germ oil; palm oils; andiroba oils;and oil from tomato residues. In particular, the composition comprisingsqualene may be derived from shark liver oil.

The purification distillation removes impurities from a compositioncomprising squalene to produce a purified composition. The compositioncomprising squalene is generally a liquid. Prior to purificationdistillation, the composition comprising squalene may contain impuritiessuch as squalamine; alkylglycerols; fatty acids (e.g. omega-3-fattyacids); vitamins A and D; pristine; triglycerides; glycerol ethers andfatty alcohols.

The purification distillation is carried out at a temperature T₁,wherein T₁ may be sufficient to cause squalene to boil, i.e. T₁ may begreater than or equal to the boiling point of squalene. The boilingpoint of squalene is 429-430° C. at 760 mm Hg (i.e. 1 atmosphere).

The boiling point of a liquid is the temperature at which the vaporpressure of the liquid phase of a compound equals the external pressureacting on the surface of the liquid. Therefore, the boiling point ofsqualene, and hence the lower limit of T₁, will depend on the externalpressure acting on the surface of the composition comprising squalene.This phenomenon is well known in the art and the skilled person would beable to calculate the observed boiling point of squalene at a givendistillation pressure used. Alternatively, the skilled person would beable to calculate the required distillation pressure based on a desiredobserved boiling point of squalene. Such calculations may be carried outusing a nomograph.

In one embodiment, the purification distillation can be carried out at atemperature of at least 70° C., e.g. at least 75° C., or at least 80° C.In another embodiment, the purification distillation can be carried outat a temperature of less than 140° C., e.g. less than 130° C., less than120° C., less than 110° C., less than 100° C. less than 95° C., lessthan 90° C., or less than 85° C.

In one embodiment, the purification distillation can be carried out in anear vacuum. In particular, the purification distillation can be carriedout at a pressure of at least 0.5 μm Hg, e.g. at least 0.75 μm Hg, or atleast 1 μm Hg. The purification distillation can be carried out at apressure of less than 5 μm Hg, e.g. less than 2.5 μm Hg, or less than 2μm Hg.

Further embodiments of the present invention comprise combinations ofthe minimum and maximum temperatures and the minimum and maximumpressures recited above.

The purification distillation can result in a composition whichcomprises at least 95% squalene, e.g. at least 96% squalene, at least97% squalene, at least 98% squalene, at least 99% squalene, at least99.5% squalene, at least 99.8% squalene, at least 99.9% squalene, oreven 100% squalene.

All percentages quoted herein are percentages by weight and may bemeasured using gas chromatography (GC). A GC technique may be conductedby injecting a sample of squalene in hexane onto a gas chromatographequipped with a flame ionization detector (FID). The analysis can beperformed on a 30 m×0.32 mm×0.50 mm capillary column maintained at 200°C. for 2 minutes and then ramped at 12° C. per minute to 310° C., whereit is held for 9 minutes. The injection port and the FID are maintainedat 300° C. and 320° C. respectively. Identity of the squalene peak isestablished using GC/MS (gas chromatography using a mass selectivedetector). Purity is reported as the area of the squalene peak as apercentage of the sum of the areas of all the peaks in the chromatogram.

The purification distillation may be carried out prior to the denaturingdistillation, resulting in a purified composition. Alternatively, thepurification distillation may be carried out after the denaturingdistillation, resulting in a denatured, purified composition.

Denaturing Distillation

Sharks, and therefore squalene derived from shark-liver oil, can containproteins to which humans are allergic. A common fish protein to whichhumans may be allergic is parvalbumin, which is found in sharks. Inaddition, contaminant proteins or materials may have been introduced tothe squalene composition, e.g. following the purification distillationor as degradation products of the squalene. Possible contaminantproteins or materials include acetone, acetaldehyde, formaldehyde, andwater. Advantageously, the denaturing distillation step denatures and/orremoves proteins, in particular parvalbumin and any contaminantproteins, from the composition comprising squalene, thus providing adenatured composition. A further advantage of the method of the presentinvention is that the denaturing distillation can ensure that anypotential viruses present in the composition comprising squalene areinactivated and/or removed from the purified composition. The denaturedcomposition is therefore safer for human use than a non-denaturedcomposition.

Without wishing to be bound by theory, the boiling point of squalenewill depend on the external pressure acting on the surface of thecomposition comprising squalene. However, the temperature at which anyproteins present in the composition comprising squalene will bedenatured is generally independent of the external pressure acting onthe surface of the composition comprising squalene. Therefore, thedenaturing distillation may be carried out at a specific temperature,irrespective of the pressure under which the distillation is performed.In particular, the denaturing distillation may be carried out at atemperature T₂, wherein T₂ may be greater than or equal to 200° C. e.g.greater than or equal to 205° C., greater than or equal to 210° C.,greater than or equal to 215° C., greater than or equal to 220° C.,greater than or equal to 230° C., greater than or equal to 240° C.,greater than or equal to 250° C., or greater than or equal to 260° C.

The denaturing distillation may be carried out at a temperature of lessthan 500° C., e.g. less than 480° C., less than 450° C., less than 420°C., less than 400° C., less than 350° C., or less than 300° C.

The denaturing distillation can be carried out at a near vacuum. Inparticular, the denaturing distillation can be carried out at a pressureof at least 0.5 mm Hg, e.g. at least 0.6 mm Hg, at least 0.7 mm Hg, orat least 0.8 mm Hg. The denaturing distillation can be carried out at apressure of less than 5 mm Hg, e.g. less than 4 mm Hg, less than 3 mmHg, less than 2 mm Hg, less than 1.5 mm Hg, less than 1 mm Hg, or lessthan 0.9 mm Hg.

Further embodiments of the present invention comprise combinations ofthe minimum and maximum temperatures and the minimum and maximumpressures recited above.

To carry out the denaturing distillation at such a high temperature, itmay be advantageous to use an apparatus in which the compositioncomprising squalene is brought into contact with a hot surface. The hotsurface may be maintained at the temperature T₂, as defined above, andthe pressure surrounding the hot surface may be the pressures definedabove for the denaturing distillation. The pressure surrounding the hotsurface may be selected to ensure that the observed boiling point ofsqualene is T₂ or less. As the composition comprising squalene iscontacted with the hot surface, those components of the composition,including squalene, whose boiling point is below T₂ at the pressuresurrounding the hot surface will volatilize. Non-volatile components,e.g. proteins, remain on the hot surface and may be denatured andseparated from the squalene.

Prior to the denaturing distillation, the composition comprisingsqualene may comprise from 85% to 99.9% squalene, e.g. from 90% to 99.5%squalene, from 95% to 99.5% squalene, or from 97% to 99.5% squalene.

The denaturing distillation can produce a squalene composition having ahigher percentage of squalene. In particular, the denaturingdistillation produces can result in a denatured composition comprisingat least 95% squalene, e.g. at least 99% squalene, at least 99.5%squalene, at least 99.9% squalene, or even 100% squalene.

The denaturing distillation can result in a denatured compositioncomprising less than 0.5% protein, e.g. less than 0.1% protein, lessthan 0.01% protein, or 0% protein. Therefore, the present inventionprovides squalene comprising less than 0.5% protein, e.g. less than 0.1%protein, less than 0.01% protein, or 0% protein.

In one embodiment, the denaturing distillation may be carried out afterthe purification distillation, resulting in a purified, denaturedcomposition.

T₂ may be greater than T₁. In particular, T₂-T₁ may be from 10° C. to300° C., e.g. from 30° C. to 250° C., from 50° C. to 200° C., or from80° C. to 150° C.

Solvents

To avoid the introduction of impurities to the composition comprisingsqualene, which is particularly important if the squalene composition isintended for use in vaccines, the purification and denaturingdistillations may be carried out without the addition of solvents.

Saponification

The composition comprising squalene may be subjected to saponification.Saponification will usually be carried out prior to distillation steps(a) and (b), discussed above. Alternatively, saponification may becarried out in between distillation steps (a) and (b), in whicheverorder they are performed. Alternatively, but unusually, saponificationmay be carried out after distillation steps (a) and (b). Saponificationmay destroy proteins present in the composition comprising squalene.However, saponification may not remove all the proteins present. Anyresidual proteins remaining in the composition comprising squalene aftersaponification may be removed though a denaturing distillation step. Thecombination of saponification and denaturing distillation isadvantageous as it improves the chances that the squalene does notcontain any proteins.

Saponification is the hydrolysis of an ester under basic conditions toform an alcohol and the salt of a carboxylic acid. During saponificationof the composition comprising squalene, a base (e.g. NaOH or KOH) isadded to the composition which can cause the fatty acid esters (e.g. thetriglycerides) to convert into soap. Saponification may be advantageousbecause it can increase the difference between the boiling points of thesaponified products and the boiling points of the unsaponified products,making separation by distillation, e.g. the purification and/or thedenaturing distillation, more efficient. Alternatively, the saponifiedproducts may be removed by another means, e.g. by centrifugation.

The removal of the fatty acid esters by saponification can result in asaponified composition comprising squalene, which can be of improvedpurity (i.e. a higher % of squalene) compared to the unsaponifiedcomposition comprising squalene.

Squalene Characterization

The squalene produced by the method of the present invention may have asaponification value of less than 4 mg/ml, e.g. less than 3 mg/ml, lessthan 2 mg/ml, or less than 1 mg/ml. This measurement indicates theamount of saponifiable species present in the squalene. Thesaponification value may be determined as the hydrolyzing andneutralizing equivalents of sodium hydroxide as described in USPharmacopeia (USP)<401>. A saponification value obtained using NaOH canbe converted to a KOH values by multiplying it by the ratio of themolecular weights of KOH and NaOH (1.403).

The squalene produced by the method of the present invention may have anacid value of less than or equal to 1 mg KOH/g, e.g. less than or equalto 0.8 mg KOH/g, less than or equal to 0.6 mg KOH/g, less than or equalto 0.5 mg KOH/g, less than or equal to 0.4 mg KOH/g, less than or equalto 0.2 mg KOH/g, less than or equal to 0.1 mg KOH/g, less than or equalto 0.05 mg KOH/g, less than or equal to 0.03 mg KOH/g, less than orequal to 0.02 mg KOH/g, or less than or equal to 0.01 mg KOH/g. The acidvalue may be determined as the as the neutralizing equivalents ofpotassium hydroxide consumed by squalene as described in USP <401>.

Oil-in-Water Emulsions

Once the composition comprising squalene has been prepared as describedabove, it can be used for preparation of downstream products e.g.medicines, oil-in-water emulsion adjuvants, etc.

To avoid contamination, it is preferable that squalene be kept sterilefollowing distillation treatment and prior to the preparation of thedownstream product. For example, if the downstream product is anemulsion, the distillation and emulsion apparatuses could form a closedsystem to avoid contamination of the squalene prior to formation of theemulsion. Alternatively or in addition, the squalene could be kept underan inert atmosphere, e.g. nitrogen, prior to preparation of thedownstream product.

Oil-in-water emulsions have been found to be particularly suitable foruse in adjuvanting vaccines. Emulsions prepared according to theinvention include squalene and at least one surfactant, in addition toan aqueous component. The emulsions may contain additional oils.Ideally, the oil(s) and surfactant(s) are biodegradable (metabolisable)and biocompatible.

Oil combinations of squalene and tocopherols can be used. Where acomposition includes a tocopherol, any of the α β γ δ ε or ξ tocopherolscan be used, but α-tocopherols are preferred. D-α-tocopherol andDL-α-tocopherol can both be used. A preferred α-tocopherol isDL-α-tocopherol. The tocopherol can take several forms e.g. differentsalts and/or isomers. Salts include organic salts, such as succinate,acetate, nicotinate, etc. If a salt of a tocopherol is used, thepreferred salt is the succinate. An oil combination comprising squaleneand a tocopherol (e.g. DL-α-tocopherol) is useful.

An oil content in the range of 2-20% (by volume) is typical.

The aqueous component can be plain water (e.g. w.f.i.) or can includefurther components e.g. solutes. For instance, it may include salts toform a buffer e.g. citrate or phosphate salts, such as sodium salts.Typical buffers include: a phosphate buffer; a Tris buffer; a boratebuffer; a succinate buffer; a histidine buffer; or a citrate buffer.Buffers will typically be included in the 5-20 mM range.

The surfactant is preferably biodegradable (metabolisable) andbiocompatible. Surfactants can be classified by their ‘HLB’(hydrophile/lipophile balance), where a HLB in the range 1-10 generallymeans that the surfactant is more soluble in oil than in water, and aHLB in the range 10-20 are more soluble in water than in oil. Emulsionspreferably comprise at least one surfactant that has a HLB of at least10 e.g. at least 15, or preferably at least 16.

The invention can be used with surfactants including, but not limitedto: the polyoxyethylene sorbitan esters surfactants (commonly referredto as the Tweens), especially polysorbate 20 and polysorbate 80;copolymers of ethylene oxide (EO), propylene oxide (PO), and/or butyleneoxide (BO), sold under the DOWFAX™ tradename, such as linear EO/PO blockcopolymers; octoxynols, which can vary in the number of repeating ethoxy(oxy-1,2-ethanediyl) groups, with octoxynol-9 (Triton X-100, ort-octylphenoxypolyethoxyethanol) being of particular interest;(octylphenoxy)polyethoxyethanol (IGEPAL CA-630/NP-40); phospholipidssuch as phosphatidylcholine (lecithin); polyoxyethylene fatty ethersderived from lauryl, cetyl, stearyl and oleyl alcohols (known as Brijsurfactants), such as triethyleneglycol monolauryl ether (Brij 30);polyoxyethylene-9-lauryl ether; and sorbitan esters (commonly known asthe SPANs), such as sorbitan trioleate (Span 85) and sorbitanmonolaurate. Preferred surfactants for including in the emulsion arepolysorbate 80 (Tween 80; polyoxyethylene sorbitan monooleate), Span 85(sorbitan trioleate), lecithin and Triton X-100.

Mixtures of surfactants can be included in the emulsion e.g. Tween80/Span 85 mixtures, or Tween 80/Triton-X100 mixtures. A combination ofa polyoxyethylene sorbitan ester such as polyoxyethylene sorbitanmonooleate (Tween 80) and an octoxynol such ast-octylphenoxy-polyethoxyethanol (Triton X-100) is also suitable.Another useful combination comprises laureth 9 plus a polyoxyethylenesorbitan ester and/or an octoxynol. Useful mixtures can comprise asurfactant with a HLB value in the range of 10-20 (e.g. Tween 80, with aHLB of 15.0) and a surfactant with a HLB value in the range of 1-10(e.g. Span 85, with a HLB of 1.8).

Preferred amounts of surfactants (% by weight) are: polyoxyethylenesorbitan esters (such as Tween 80) 0.01 to 2%; octyl- or nonylphenoxypolyoxyethanols (such as Triton X-100, or other Triton seriesdetergents) 0.001 to 0.1%; polyoxyethylene ethers (such as laureth 9)0.1 to 20%.

Squalene-containing oil-in-water emulsions containing polysorbate 80surfactant are preferred.

The oil-in-water emulsion may be manufactured using a method comprisingthe steps of: (i) preparation of a first emulsion having a first averageoil droplet size, also known as a preliminary emulsion or apre-emulsion; (ii) microfluidization of the first emulsion to form asecond emulsion having a second average oil droplet size which is lessthan the first average oil droplet size; and (iii) filtration of thesecond emulsion. The first emulsion may be prepared throughhomogenization.

The oil droplets in the emulsion are generally less than 5. mu.m indiameter, and may even have a sub-micron diameter, with these smallsizes conveniently being achieved with a microfluidiser to providestable emulsions. Droplets with a size less than 220 nm are preferred asthey can be subjected to filter sterilization.

Specific oil-in-water emulsion adjuvants that can be made using squaleneprepared according to the invention include, but are not limited to:

-   -   An emulsion of squalene, polysorbate 80 (Tween 80), and sorbitan        trioleate (Span 85). The composition of the emulsion by volume        can be about 5% squalene, about 0.5% polysorbate 80 and about        0.5% Span 85. In weight terms, these ratios become 4.3%        squalene, 0.5% polysorbate 80 and 0.48% Span 85. This adjuvant        is known as ‘MF59’ [4-6], as described in more detail in Chapter        10 of ref. 7 and chapter 12 of ref 8. The MF59 emulsion        advantageously includes citrate ions e.g. 10 mM sodium citrate        buffer.    -   An emulsion of squalene, a tocopherol (ideally        DL-.alpha.-tocopherol), and polysorbate 80. These emulsions may        have (by weight) from 2 to 10% squalene, from 2 to 10%        tocopherol and from 0.3 to 3% polysorbate 80, e.g. 4.3%        squalene, 4.7% tocopherol and 1.9% polysorbate 80. The weight        ratio of squalene:tocopherol is preferably <1 (e.g. 0.90) as        this can provide a more stable emulsion. Squalene and        polysorbate 80 may be present at a volume ratio of about 5:2 or        at a weight ratio of about 11:5. One such emulsion can be made        by dissolving polysorbate 80 in PBS to give a 2% solution, then        mixing 90 ml of this solution with a mixture of (5 g of        DL-.alpha.-tocopherol and 5 ml squalene), then microfluidising        the mixture. The resulting emulsion has submicron oil droplets        e.g. with an average diameter of between 100 and 250 nm,        preferably about 180 nm. The emulsion may also include a        3-de-O-acylated monophosphoryl lipid A (3d-MPL). Another useful        emulsion of this type may comprise, per human dose, 0.5-10 mg        squalene, 0.5-11 mg tocopherol, and 0.1-4 mg polysorbate 80 [9].    -   An emulsion of squalene, a tocopherol, and a Triton detergent        (e.g. Triton X-100). The emulsion may also include a 3d-MPL. The        emulsion may contain a phosphate buffer.    -   An emulsion comprising squalene, a polysorbate (e.g. polysorbate        80), a Triton detergent (e.g. Triton X-100) and a tocopherol        (e.g. an .alpha.-tocopherol succinate). The emulsion may include        these three components at a mass ratio of about 75:11:10 (e.g.        7504 ml polysorbate 80, 110 μg/ml Triton X-100 and 100 μg/ml        .alpha.-tocopherol succinate), and these concentrations should        include any contribution of these components from antigens. The        emulsion may also include a 3d-MPL. The emulsion may also        include a saponin, such as QS21. The aqueous phase may contain a        phosphate buffer.    -   An emulsion comprising squalene, an aqueous solvent, a        polyoxyethylene alkyl ether hydrophilic nonionic surfactant        (e.g. polyoxyethylene (12) cetostearyl ether) and a hydrophobic        nonionic surfactant (e.g. a sorbitan ester or mannide ester,        such as sorbitan monoleate or ‘Span 80’). The emulsion is        preferably thermoreversible and/or has at least 90% of the oil        droplets (by volume) with a size less than 200 nm [10]. The        emulsion may also include one or more of: alditol; a        cryoprotective agent (e.g. a sugar, such as dodecylmaltoside        and/or sucrose); and/or an alkylpolyglycoside. The emulsion may        include a TLR4 agonist [11]. Such emulsions may be lyophilized.    -   An emulsion of squalene, poloxamer 105 and Abil-Care [12]. The        final concentration (weight) of these components in adjuvanted        vaccines are 5% squalene, 4% poloxamer 105 (pluronic polyol) and        2% Abil-Care 85 (Bis-PEG/PPG-16/16 PEG/PPG-16/16 dimethicone;        caprylic/capric triglyceride).

The compositions of these emulsions, expressed above in percentageterms, may be modified by dilution or concentration (e.g. by an integer,such as 2 or 3 or by a fraction, such as ⅔ or ¾), in which their ratiosstay the same. For instance, a 2-fold concentrated MF59 would have about10% squalene, about 1% polysorbate 80 and about 1% sorbitan trioleate.Concentrated forms can be diluted (e.g. with an antigen solution) togive a desired final concentration of emulsion.

Emulsions of the invention are ideally stored at between 2° C. and 8° C.They should not be frozen. They should ideally be kept out of directlight. In particular, squalene-containing emulsions and vaccines of theinvention should be protected to avoid photochemical breakdown ofsqualene. If emulsions of the invention are stored then this ispreferably in an inert atmosphere e.g. N₂ or argon.

Vaccines

Although it is possible to administer oil-in-water emulsion adjuvants ontheir own to patients (e.g. to provide an adjuvant effect for an antigenthat has been separately administered to the patient), it is more usualto admix the adjuvant with an antigen prior to administration, to forman immunogenic composition e.g. a vaccine. Mixing of emulsion andantigen may take place extemporaneously, at the time of use, or can takeplace during vaccine manufacture, prior to filling. The methods of theinvention can be applied in both situations.

Thus a method of the invention may include a further process step ofadmixing an emulsion comprising squalene prepared according to thepresent invention with an antigen component. As an alternative, it mayinclude a further step of packaging the adjuvant into a kit as a kitcomponent together with an antigen component.

Overall, therefore, the invention can be used when preparing mixedvaccines or when preparing kits including antigen and adjuvant ready formixing. Where mixing takes place during manufacture then the volumes ofbulk antigen and emulsion that are mixed will typically be greater than1 liter e.g. ≧5 liters, ≧10 liters, ≧20 liters, ≧50 liters, etc. Wheremixing takes place at the point of use then the volumes that are mixedwill typically be smaller than 1 milliliter e.g. ≦0.6 ml, ≦0.5 ml, ≦0.4ml, ≦0.3 ml, ≦0.2 ml, etc. In both cases it is usual for substantiallyequal volumes of emulsion and antigen solution to be mixed i.e.substantially 1:1 (e.g. between 1.1:1 and 1:1.1, preferably between1.05:1 and 1:1.05, and more preferably between 1.025:1 and 1:1.025). Insome embodiments, however, an excess of emulsion or an excess of antigenmay be used [13]. Where an excess volume of one component is used, theexcess will generally be at least 1.5:1 e.g. ≧2:1, ≧2.5:1, ≧3:1, ≧4:1,≧5:1, etc.

Where antigen and adjuvant are presented as separate components within akit, they are physically separate from each other within the kit, andthis separation can be achieved in various ways. For instance, thecomponents may be in separate containers, such as vials. The contents oftwo vials can then be mixed when needed e.g. by removing the contents ofone vial and adding them to the other vial, or by separately removingthe contents of both vials and mixing them in a third container.

In another arrangement, one of the kit components is in a syringe andthe other is in a container such as a vial. The syringe can be used(e.g. with a needle) to insert its contents into the vial for mixing,and the mixture can then be withdrawn into the syringe. The mixedcontents of the syringe can then be administered to a patient, typicallythrough a new sterile needle. Packing one component in a syringeeliminates the need for using a separate syringe for patientadministration.

In another preferred arrangement, the two kit components are heldtogether but separately in the same syringe e.g. a dual-chamber syringe,such as those disclosed in references 14-21 etc. When the syringe isactuated (e.g. during administration to a patient) then the contents ofthe two chambers are mixed. This arrangement avoids the need for aseparate mixing step at time of use.

The contents of the various kit components will generally all be inliquid form. In some arrangements, a component (typically the antigencomponent rather than the emulsion component) is in dry form (e.g. in alyophilized form), with the other component being in liquid form. Thetwo components can be mixed in order to reactivate the dry component andgive a liquid composition for administration to a patient. A lyophilizedcomponent will typically be located within a vial rather than a syringe.Dried components may include stabilizers such as lactose, sucrose ormannitol, as well as mixtures thereof e.g. lactose/sucrose mixtures,sucrose/mannitol mixtures, etc. One possible arrangement uses a liquidemulsion component in a pre-filled syringe and a lyophilized antigencomponent in a vial.

If vaccines contain components in addition to emulsion and antigen thenthese further components may be included in one these two kitcomponents, or may be part of a third kit component.

Suitable containers for mixed vaccines of the invention, or forindividual kit components, include vials and disposable syringes. Thesecontainers should be sterile.

Where a composition/component is located in a vial, the vial ispreferably made of a glass or plastic material. The vial is preferablysterilized before the composition is added to it. To avoid problems withlatex-sensitive patients, vials are preferably sealed with a latex-freestopper, and the absence of latex in all packaging material ispreferred. In one embodiment, a vial has a butyl rubber stopper. Thevial may include a single dose of vaccine/component, or it may includemore than one dose (a ‘multidose’ vial) e.g. 10 doses. In oneembodiment, a vial includes 10×0.25 ml doses of emulsion. Preferredvials are made of colorless glass.

A vial can have a cap (e.g. a Luer lock) adapted such that a pre-filledsyringe can be inserted into the cap, the contents of the syringe can beexpelled into the vial (e.g. to reconstitute lyophilized materialtherein), and the contents of the vial can be removed back into thesyringe. After removal of the syringe from the vial, a needle can thenbe attached and the composition can be administered to a patient. Thecap is preferably located inside a seal or cover, such that the seal orcover has to be removed before the cap can be accessed.

Where a composition/component is packaged into a syringe, the syringewill not normally have a needle attached to it, although a separateneedle may be supplied with the syringe for assembly and use. Safetyneedles are preferred. 1-inch 23-gauge, 1-inch 25-gauge and ⅝-inch25-gauge needles are typical. Syringes may be provided with peel-offlabels on which the lot number, influenza season and expiration date ofthe contents may be printed, to facilitate record keeping. The plungerin the syringe preferably has a stopper to prevent the plunger frombeing accidentally removed during aspiration. The syringes may have alatex rubber cap and/or plunger. Disposable syringes contain a singledose of vaccine. The syringe will generally have a tip cap to seal thetip prior to attachment of a needle, and the tip cap is preferably madeof a butyl rubber. If the syringe and needle are packaged separatelythen the needle is preferably fitted with a butyl rubber shield.

The emulsion may be diluted with a buffer prior to packaging into a vialor a syringe. Typical buffers include: a phosphate buffer; a Trisbuffer; a borate buffer; a succinate buffer; a histidine buffer; or acitrate buffer. Dilution can reduce the concentration of the adjuvant'scomponents while retaining their relative proportions e.g. to provide a“half-strength” adjuvant.

Containers may be marked to show a half-dose volume e.g. to facilitatedelivery to children. For instance, a syringe containing a 0.5 ml dosemay have a mark showing a 0.25 ml volume.

Where a glass container (e.g. a syringe or a vial) is used, then it ispreferred to use a container made from a borosilicate glass rather thanfrom a soda lime glass.

Various antigens can be used with oil-in-water emulsions, including butnot limited to: viral antigens, such as viral surface proteins;bacterial antigens, such as protein and/or saccharide antigens; fungalantigens; parasite antigens; and tumor antigens. The invention isparticularly useful for vaccines against influenza virus, HIV, hookworm,hepatitis B virus, herpes simplex virus, rabies, respiratory syncytialvirus, cytomegalovirus, Staphylococcus aureus, chlamydia, SARScoronavirus, varicella zoster virus, Streptococcus pneumoniae, Neisseriameningitidis, Mycobacterium tuberculosis, Bacillus anthracis, EpsteinBarr virus, human papillomavirus, etc. For example:

-   -   Influenza virus antigens. These may take the form of a live        virus or an inactivated virus. Where an inactivated virus is        used, the vaccine may comprise whole virion, split virion, or        purified surface antigens (including hemagglutinin and, usually,        also including neuraminidase). Influenza antigens can also be        presented in the form of virosomes. The antigens may have any        hemagglutinin subtype, selected from H1, H2, H3, H4, H5, H6, H7,        H8, H9, H10, H11, H12, H13, H14, H15 and/or H16. Vaccine may        include antigen(s) from one or more (e.g. 1, 2, 3, 4 or more)        influenza virus strains, including influenza A virus and/or        influenza B virus, e.g. a monovalent A/H5N1 or A/H1N1 vaccine,        or a trivalent A/H1N1+A/H3N2+B vaccine. The influenza virus may        be a reassortant strain, and may have been obtained by reverse        genetics techniques [e.g. 22-26]. Thus the virus may include one        or more RNA segments from a A/PR/8/34 virus (typically 6        segments from A/PR/8/34, with the HA and N segments being from a        vaccine strain, i.e. a 6:2 reassortant). The viruses used as the        source of the antigens can be grown either on eggs (e.g.        embryonated hen eggs) or on cell culture. Where cell culture is        used, the cell substrate will typically be a mammalian cell        line, such as MDCK; CHO; 293T; BHK; Vero; MRC-5; PER.C6; WI-38;        etc. Preferred mammalian cell lines for growing influenza        viruses include: MDCK cells [27-30], derived from Madin Darby        canine kidney; Vero cells [31-33], derived from African green        monkey kidney; or PER.C6 cells [34], derived from human        embryonic retinoblasts. Where virus has been grown on a        mammalian cell line then the composition will advantageously be        free from egg proteins (e.g. ovalbumin and ovomucoid) and from        chicken DNA, thereby reducing allergenicity. Unit doses of        vaccine are typically standardized by reference to hemagglutinin        (HA) content, typically measured by SRID. Existing vaccines        typically contain about 15 μg of HA per strain, although lower        doses can be used, particularly when using an adjuvant.        Fractional doses such as ½ (i.e. 7.5 μg HA per strain), ¼ and ⅛        have been used [35,36], as have higher doses (e.g. 3× or 9×        doses [37,38]). Thus vaccines may include between 0.1 and 150 μg        of HA per influenza strain, preferably between 0.1 and 50 μg        e.g. 0.1-20 μg, 0.1-15 μg, 0.1-10 μg, 0.5-5 μg, etc. Particular        doses include e.g. about 15, about 10, about 7.5, about 5, about        3.8, about 3.75, about 1.9, about 1.5, etc. per strain. Human        immunodeficiency virus, including HIV-1 and HIV-2. The antigen        will typically be an envelope antigen.    -   Hepatitis B virus surface antigens. This antigen is preferably        obtained by recombinant DNA methods e.g. after expression in a        Saccharomyces cerevisiae yeast. Unlike native viral HBsAg, the        recombinant yeast-expressed antigen is non-glycosylated. It can        be in the form of substantially-spherical particles (average        diameter of about 20 nm), including a lipid matrix comprising        phospholipids. Unlike native HBsAg particles, the        yeast-expressed particles may include phosphatidylinositol. The        HBsAg may be from any of subtypes ayw1, ayw2, ayw3, ayw4, ayr,        adw2, adw4, adrq- and adrq+.    -   Hookworm, particularly as seen in canines (Ancylostoma caninum).        This antigen may be recombinant Ac-MTP-1 (astacin-like        metalloprotease) and/or an aspartic hemoglobinase (Ac-APR-1),        which may be expressed in a baculovirus/insect cell system as a        secreted protein [39,40].    -   Herpes simplex virus antigens (HSV). A preferred HSV antigen for        use with the invention is membrane glycoprotein gD. It is        preferred to use gD from a HSV-2 strain (‘gD2’ antigen). The        composition can use a form of gD in which the C-terminal        membrane anchor region has been deleted [41] e.g. a truncated gD        comprising amino acids 1-306 of the natural protein with the        addition of aparagine and glutamine at the C-terminus. This form        of the protein includes the signal peptide which is cleaved to        yield a mature 283 amino acid protein. Deletion of the anchor        allows the protein to be prepared in soluble form.    -   Human papillomavirus antigens (HPV). Preferred HPV antigens for        use with the invention are L1 capsid proteins, which can        assemble to form structures known as virus-like particles        (VLPs). The VLPs can be produced by recombinant expression of L1        in yeast cells (e.g. in S. cerevisiae) or in insect cells (e.g.        in Spodoptera cells, such as S. frugiperda, or in Drosophila        cells). For yeast cells, plasmid vectors can carry the L1        gene(s); for insect cells, baculovirus vectors can carry the L1        gene(s). More preferably, the composition includes L1 VLPs from        both HPV-16 and HPV-18 strains. This bivalent combination has        been shown to be highly effective [42]. In addition to HPV-16        and HPV-18 strains, it is also possible to include L1 VLPs from        HPV-6 and HPV-11 strains. The use of oncogenic HPV strains is        also possible. A vaccine may include between 20-60 μg/ml (e.g.        about 40 μg/ml) of L1 per HPV strain.    -   Anthrax antigens. Anthrax is caused by Bacillus anthracis.        Suitable B. anthracis antigens include A-components (lethal        factor (LF) and edema factor (EF)), both of which can share a        common B-component known as protective antigen (PA). The        antigens may optionally be detoxified. Further details can be        found in references [43 to 45].    -   S. aureus antigens. A variety of S. aureus antigens are known.        Suitable antigens include capsular saccharides (e.g. from a type        5 and/or type 8 strain) and proteins (e.g. IsdB, Hla, etc.).        Capsular saccharide antigens are ideally conjugated to a carrier        protein.    -   S. pneumoniae antigens. A variety of S. pneumoniae antigens are        known. Suitable antigens include capsular saccharides (e.g. from        one or more of serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F,        and/or 23F) and proteins (e.g. pneumolysin, detoxified        pneumolysin, polyhistidine triad protein D (PhtD), etc.).        Capsular saccharide antigens are ideally conjugated to a carrier        protein.    -   Cancer antigens. A variety of tumour-specific antigens are        known. The invention may be used with antigens that elicit an        immunotherapeutic response against lung cancer, A solution of        the antigen will normally be mixed with the squalene-containing        emulsion e.g. at a 1:1 volume ratio. This mixing can either be        performed by a vaccine manufacturer, prior to filling, or can be        performed at the point of use, by a healthcare worker.

Pharmaceutical Compositions

Compositions made using the methods of the invention arepharmaceutically acceptable. They may include components in addition tothe squalene-containing emulsion and the optional antigen.

The composition may include a preservative such as thiomersal or2-phenoxyethanol. It is preferred, however, that the vaccine should besubstantially free from (i.e. less than 5 μg/ml) mercurial material e.g.thiomersal-free [46,47]. Vaccines and components containing no mercuryare more preferred.

The pH of a composition will generally be between 5.0 and 8.1, and moretypically between 6.0 and 8.0 e.g. between 6.5 and 7.5. A process of theinvention may therefore include a step of adjusting the pH of thevaccine prior to packaging.

The composition is preferably sterile. The composition is preferablynon-pyrogenic e.g. containing <1 EU (endotoxin unit, a standard measure)per dose, and preferably <0.1 EU per dose. The composition is preferablygluten free.

The composition may include material for a single immunization, or mayinclude material for multiple immunizations (i.e. a ‘multidose’ kit).The inclusion of a preservative is preferred in multidose arrangements.

Vaccines are typically administered in a dosage volume of about 0.5 ml,although a half dose (i.e. about 0.25 ml) may be administered tochildren.

Methods of Treatment, and Administration of the Vaccine

The invention provides kits and compositions prepared using the methodsof the invention. The compositions prepared according to the methods ofthe invention are suitable for administration to human patients, and theinvention provides a method of raising an immune response in a patient,comprising the step of administering such a composition to the patient.

The invention also provides these kits and compositions for use asmedicaments.

The invention also provides the use of: (i) an aqueous preparation of anantigen; and (ii) an oil-in-water emulsion comprising squalene preparedaccording to the invention, in the manufacture of a medicament forraising an immune response in a patient.

The immune response raised by these methods and uses will generallyinclude an antibody response, preferably a protective antibody response.

The compositions can be administered in various ways. The most preferredimmunization route is by intramuscular injection (e.g. into the arm orleg), but other available routes include subcutaneous injection,intranasal [48-50], oral [51], intradermal [52,53], transcutaneous,transdermal [54], etc.

Vaccines prepared according to the invention may be used to treat bothchildren and adults. The patient may be less than 1 year old, 1-5 yearsold, 5-15 years old, 15-55 years old, or at least 55 years old. Thepatient may be elderly (e.g. ≧50 years old, preferably ≧65 years), theyoung (e.g. ≦5 years old), hospitalized patients, healthcare workers,armed service and military personnel, pregnant women, the chronicallyill, immunodeficient patients, and people travelling abroad. Thevaccines are not suitable solely for these groups, however, and may beused more generally in a population.

Vaccines of the invention may be administered to patients atsubstantially the same time as (e.g. during the same medicalconsultation or visit to a healthcare professional) other vaccines.

General

The term “comprising” encompasses “including” as well as “consisting”e.g. a composition “comprising” X may consist exclusively of X or mayinclude something additional e.g. X+Y.

The term “about” in relation to a numerical value x is optional andmeans, for example, x±10%.

The word “substantially” does not exclude “completely” e.g. acomposition which is “substantially free” from Y may be completely freefrom Y. Where necessary, the word “substantially” may be omitted fromthe definition of the invention.

Unless specifically stated, a process comprising a step of mixing two ormore components does not require any specific order of mixing. Thuscomponents can be mixed in any order. Where there are three componentsthen two components can be combined with each other, and then thecombination may be combined with the third component, etc.

The various steps of the methods may be carried out at the same ordifferent times, in the same or different geographical locations, e.g.countries, and by the same or different people or entities.

MODES FOR CARRYING OUT THE INVENTION Example 1

FIG. 1 shows a schematic of a distillation apparatus which may be usedfor the purification and/or denaturing distillation steps of the methodof the present invention. The process described with reference to FIG. 1may be carried out without the addition of any solvent to thecomposition comprising squalene. In the embodiment shown in FIG. 1, thecomposition comprising squalene is placed in a feed vessel (1) overlaidwith nitrogen. One end of an inlet line (3) has a polypropyleneprefilter and is placed in the feed vessel, while the other end of theinlet line has a stainless steel needle (19-ga.) which is inserted intothe top of a distillation apparatus (5). The distillation apparatuscomprises a chamber (7) shaped like a tube with a cylindrical “hotfinger” (9) protruding through the centre. Ethyl benzoate, which has aboiling point of 212° C., is heated below the finger to provide heat tothe wall of the hot finger. Although ethyl benzoate is used in thisembodiment, it is clear that a solvent having a higher boiling pointcould be used to increase the temperature of the hot finger. Duringdistillation, the distillation apparatus may be evacuated. Thecomposition comprising squalene may be drawn into the distillationapparatus, e.g. through the use of a lower pressure within thedistillation apparatus, through the stainless steel needle and dripped(11) onto the heated wall of the hot finger. As the compositioncomprising squalene is heated, those components whose boiling point isbelow 212° C. at the pressure within the distillation apparatus willvolatilize. In order to volatilize squalene using the system of FIG. 1,the pressure within the distillation apparatus should be selected tolower the boiling point of squalene to 212° C. or less (e.g.approximately 1.5 mm Hg or less). The volatilized components willcondense on the outer wall of the chamber (7), which will be cooled bythe ambient air, and will run down the walls into a collection flask(13), which may also be under vacuum. Non-volatile components, e.g.proteins, remain on the wall of the hot finger and flow down into theresidue flask (15). Extremely volatile components may be drawn offthrough the vacuum line, reducing their levels in the squalenecondensate.

Squalene which has already been subjected to purification distillationwas distilled using this apparatus. Regardless of source, the finalsqualene regularly had a purity of ≧99.9%, an acid value of <0.03 mgKOH/g, and a saponification value <2 mg/g. The denaturing distillationreduced the moisture content of the squalene e.g. from 0.022% to 0.010%,from 0.006 to 0.005%, or from 0.010% to 0.006%.

Example 2 Measurement of the Saponification Value

The saponification value is the number of mg of potassium hydroxiderequired to neutralize the free acids and saponify the esters containedin 1.0 g of the substance.

Procedure (USP <401>): place 1.5 g to 2 g of the substance in a tared,250 mL flask, weigh accurately, and add it to 25.0 mL of a 0.5 Nalcoholic potassium hydroxide. Heat the flask on a steam bath, under asuitable condenser to maintain reflux for 30 minutes, frequentlyrotating the contents. Then add 1 mL of phenolphthalein TS, and titratethe excess potassium hydroxide with 0.5N hydrochloric acid VS. Perform ablank determination under the same conditions. The difference betweenthe volumes, in mL, of 0.5 N hydrochloric acid consumed in the actualtest and in the blank test, multiplied by 56.1 and the exact normalityof the 0.5N hydrochloric acid VS, and divided by the weight in g of thespecimen taken, is the saponification value.

Depending on the source of the squalene, a saponification value of <1.4mg/g could be obtained.

Example 3 Measurement of the Acid Value

The acidity of fats and fixed oils may be expressed as the number of mLof 0.1 N alkali required to neutralize the free acids in 10.0 g ofsubstance. The Acid Value is the number of mg of alkali required toneutralize the free acids in 1.0 g of the substance.

Procedure (USP <401>): dissolve about 10.0 g of the substance,accurately weighed, in 50 mL of a mixture of equal volumes of alcoholand ether (which has been neutralized to phenolphthalein with 0.1 Nsodium hydroxide) contained in a flask. If the test specimen does notdissolve in the cold solvent, connect the flask with a suitablecondenser and warm slowly, with frequent shaking, until the specimendissolves. Add 1 mL of phenolphthalein TS, and titrate with 0.1 N sodiumhydroxide VS until the solution remains faintly pink after shaking for30 seconds. Calculate either the Acid Value. If the volume of 0.1 Nalkali VS required for the titration is less than 2 mL, a more dilutetitrant may be used, or the sample size may be adjusted accordingly. Theresults may be expressed in terms of the volume of titrant or in termsof the equivalent volume of 0.1 N sodium hydroxide.

Depending on the source of the squalene, an acid value of 0.03 mg KOH/gcould be obtained.

Example 4 Spiking Studies

A number of spiking studies were carried out to demonstrate the efficacyof the denaturing distillation.

To determine the levels of impurity removed by the denaturingdistillation, a squalene composition was spiked with specifiedquantities of contaminants (e.g. water) as well as possibledecomposition products of the squalene (e.g. formaldehyde, acetaldehydeand acetone). The spiked solutions underwent a denaturing distillationaccording to the present invention and were analyzed for the spikedspecies.

4 kg of a squalene composition was spiked e.g. with 0.3 mL (0.2 g) ofacetaldehyde (>99.5% purity), 0.3 mL (0.2 g) of acetone (>99.9% purity),0.55 mL of 37 wt. % aqueous solution of formaldehyde (0.2 g) and 3.65 gwater prior to a denaturing distillation as described in example 1. Thedistillate was collected in three fractions and analyzed for the spikedspecies alongside the spiked starting material. The results arepresented in Table 1 below:

TABLE 1 Denaturing distillation fractions Waste Spiked First SecondThird Non- Starting Frac- Frac- Frac- volatile Test/Method Material tiontion tion Residue Moisture Content 0.02 0.03 0.02 0.02 N/A (%) Acetone50.9 5.0 5.7 1.1 N/A (mg/Kg or ppm) Acetaldehyde 12.4 0.9 1.9 0.9 N/A(mg/Kg or ppm) Formaldehyde 2.2 0.7 0.9 not N/A (mg/Kg or ppm) detected

The results in Table 1 show that the acetone, acetaldehyde andformaldehyde concentrations all decreased following the denaturingdistillation.

It will be understood that the invention has been described by way ofexample only and modifications may be made whilst remaining within thescope and spirit of the invention.

The invention claimed is:
 1. A method for the manufacture of anoil-in-water emulsion comprising: i. obtaining squalene prepared from afish oil source by a process comprising subjecting fish oil comprisingsqualene to: (a) a purification distillation carried out at near vacuum;and (b) a denaturing distillation carried out at a temperature greaterthan or equal to 210° C. at a pressure of 0.8 to 5.0 mmHg, wherein thetemperature in the denaturing distillation exceeds the temperature inthe purification distillation; and wherein the conditions for both thepurification and the denaturing distillation are sufficient to causesqualene to boil; and wherein the denaturing distillation denaturesand/or removes potential contaminant proteins and viruses, therebyrendering the squalene safe for human use as compared with non-denaturedsqualene; and ii. preparing an oil-in-water emulsion using the squalenefrom step (i).
 2. The method of claim 1, wherein the purificationdistillation occurs at a temperature of less than 140° C.
 3. The methodof claim 1, wherein the squalene prepared in step (i) is kept sterilefollowing distillation treatment and prior to the preparation of theoil-in-water emulsion.
 4. The method of claim 1, wherein the fish oilcomprises one or more contaminant proteins.
 5. The method of claim 4,wherein the contaminant protein comprises parvalbumin.
 6. The method ofclaim 1, wherein the purification distillation is carried out at atemperature of from 70 to 100° C.
 7. The method of claim 1, wherein thepurification distillation is carried out at a pressure of from 0.5 μm Hgto 5 μm Hg.
 8. The method of claim 1, wherein the purificationdistillation is carried out prior to the denaturing distillation.
 9. Themethod of claim 1, which further comprises a step of subjecting the fishoil to saponification prior to conducting the purification distillationand denaturing distillation steps.
 10. The method of claim 1, whichfurther comprises a step of subjecting the fish oil to saponificationbefore conducting the denaturing distillation step.
 11. The method ofclaim 9, wherein saponification comprises the addition of NaOH or KOH tothe fish oil.
 12. The method of claim 10, wherein saponificationcomprises the addition of NaOH or KOH to the fish oil.
 13. The method ofclaim 1, wherein the purification distillation results in a compositioncomprising 99% squalene or more.
 14. The method of claim 1, wherein thefish oil is shark liver oil.
 15. The method of claim 1, furthercomprising the step of combining the oil-in-water emulsion with anantigen.
 16. The method of claim 1, further comprising the step ofpackaging the oil-in-water emulsion into a kit as a kit componenttogether with an antigen component.
 17. The method of claim 16, whereinthe kit components are in separate vials.
 18. The method of claim 17,wherein the vials are made from borosilicate glass.
 19. The method ofclaim 15, wherein the antigen is an influenza virus antigen.
 20. Themethod of claim 19, wherein the combination of the oil-in-water emulsionand the antigen forms a vaccine composition and wherein the vaccinecomposition includes about 15 μg; about 10 μg, about 7.5 μg, about 5 μg,about 3.8 μg, about 3.75 μg, about 1.9 μg, or about 1.5 μg ofhemagglutinin per influenza virus strain.
 21. The method of claim 19,wherein the combination of the oil-in-water emulsion and the antigenforms a vaccine composition and wherein the vaccine composition includesa thiomersal or 2-phenoxyethanol preservative.
 22. The method of claim1, wherein the oil-in-water emulsion comprises between 2-10% squalene.23. The method of claim 1, wherein the oil-in-water emulsion comprisessqualene, polysorbate 80 and sorbitan trioleate.
 24. A method forprocessing squalene from a fish source, said method comprising the stepsof: i providing a composition comprising distilled squalene which hasbeen obtained by a process of distillation, and wherein the squalene isfrom a fish source; and ii re-distilling the composition from (i) at atemperature sufficient to cause the distilled squalene to boil, so as toprovide a composition comprising re-distilled squalene; wherein theprocess of distillation is performed at a temperature less than 140° C.and at a near vacuum and the process of re-distillation is performed ata temperature greater than or equal to 210° C. and a pressure of 0.8 to5.0 mmHg; and wherein the conditions for both the distillation and there-distillation are sufficient to cause the squalene to boil; andwherein the denaturing distillation denatures and/or removes potentialcontaminant proteins and viruses, thereby rendering the squalene saferfor human use as compared with non-denatured squalene.
 25. A method forthe manufacture of an oil-in-water emulsion comprising: i. obtainingsqualene prepared from a fish oil source by a process comprisingsubjecting fish oil comprising squalene to: (a) a purificationdistillation carried out at near vacuum at a temperature of less than140° C.; and (b) a denaturing distillation carried out at a temperaturegreater than or equal to 210° C., wherein the conditions for both thepurification and the denaturing distillation are sufficient to causesqualene to boil; and wherein the denaturing distillation denaturesand/or removes potential contaminant proteins and viruses, therebyrendering the squalene safe for human use as compared with non-denaturedsqualene; and ii. preparing an oil-in-water emulsion using the squalenefrom step (i).
 26. The method of claim 25, wherein the squalene preparedin step (i) is kept sterile following distillation treatment and priorto the preparation of the oil-in-water emulsion.
 27. The method of claim25, wherein the fish oil comprises one or more contaminant proteins. 28.The method of claim 27, wherein the contaminant protein comprisesparvalbumin.
 29. The method of claim 25, wherein the purificationdistillation is carried out at a temperature of from 70 to 100° C. 30.The method of claim 25, wherein the purification distillation is carriedout at a pressure of from 0.5 μm Hg to 5 μm Hg.
 31. The method of claim25, wherein the purification distillation is carried out prior to thedenaturing distillation.
 32. The method of claim 25, which furthercomprises a step of subjecting the fish oil to saponification prior toconducting the purification distillation and denaturing distillationsteps.
 33. The method of claim 25, which further comprises a step ofsubjecting the fish oil to saponification before conducting thedenaturing distillation step.
 34. The method of claim 32, whereinsaponification comprises the addition of NaOH or KOH to the fish oil.35. The method of claim 33, wherein saponification comprises theaddition of NaOH or KOH to the fish oil.
 36. The method of claim 25,wherein the purification distillation results in a compositioncomprising 99% squalene or more.
 37. The method of claim 25, wherein thefish oil is shark liver oil.
 38. The method of claim 25, furthercomprising the step of combining the oil-in-water emulsion with anantigen.
 39. The method of claim 25, further comprising the step ofpackaging the oil-in-water emulsion into a kit as a kit componenttogether with an antigen component.
 40. The method of claim 39, whereinthe kit components are in separate vials.
 41. The method of claim 40,wherein the vials are made from borosilicate glass.
 42. The method ofclaim 39, wherein the antigen is an influenza virus antigen.
 43. Themethod of claim 42, wherein the combination of the oil-in-water emulsionand the antigen forms a vaccine composition and wherein the vaccinecomposition includes about 15 μg; about 10 μg, about 7.5 μg, about 5 μg,about 3.8 μg, about 3.75 μg, about 1.9 μg, or about 1.5 μg ofhemagglutinin per influenza virus strain.
 44. The method of claim 42,wherein the combination of the oil-in-water emulsion and the antigenforms a vaccine composition and wherein the vaccine composition includesa thimersal or 2-phenoxyethanol preservative.
 45. The method of claim25, wherein the oil-in-water emulsion comprises between 2-10% squalene.46. The method of claim 25, wherein the oil-in-water emulsion comprisessqualene, polysorbate 80 and sorbitan trioleate.
 47. A method for themanufacture of an oil-in-water emulsion comprising: i. obtainingsqualene prepared from a fish oil source by a process comprisingsubjecting fish oil comprising squalene to: (a) a purificationdistillation carried out at near vacuum; and (b) a denaturingdistillation carried out at a temperature greater than or equal to 210°C. at a pressure of 0.8 to 5.0 mmHg, wherein the temperature in thedenaturing distillation exceeds the temperature in the purificationdistillation; and wherein the conditions for both the purification andthe denaturing distillation are sufficient to cause squalene to boil;and wherein the denaturing distillation denatures and/or removespotential contaminant proteins and viruses, thereby rendering thesqualene safe for human use as compared with non-denatured squalene; andii. preparing an oil-in-water emulsion using the squalene from step (i)by: (a) preparing a first emulsion having a first average droplet size;(b) microfluidizing the first emulsion to form a second emulsion havinga second average droplet size which is less than the first average oildroplet size; and (c) filtering the second emulsion; wherein the oildroplets in the oil-in-water emulsion have a diameter less than 5 μm.